Stormweaver in Season 10 is still easily one of the best casters with some of the most robust kits available. Having a teleport is still a good mobility advantage and being able to seamlessly transition between different builds and have variable options is great. StormCloud and Stormbolt make for an easy experience in the early and mid game while Lightning Surge still remains to be a potential powerhouse late game with high-end items. Either build is viable and totally possible to take to the highest parts of the game.
The mobility hit does feel bad but I still think
Stormweaver is strong. We did here mention that there are Light Radius nodes potentially used for Magic Caster scaling that could be, in theory, very good. It's going to be challenging to push it as high as we used to when it was stronger with Lightning Surge constantly proccing small StormClouds under things. You can place StormCloud/Stormbolt pretty high up into the game with the correct gear and enough skill, haste, and AoE damage stacking.
Lightning Surge will be doing less damage with Chain Lightning now being an 18% proc instead of 100% This means it is a bit less clear, though, with how many targets it hits. It should still go off fairly often. It did receive a 0.5% upgrade in damage per point but that's probably not enough to offset the loss. Pulsing Charge got a massive buff though it did get a proc chance. However given the damage increase a god. I think it will actually do more damage even with the proc chance. However Charge Bolts and the electric field Nova augment did get a damage reduction as well, which is a weird choice considering they just buffed what might make Charge Bolts good. We'll have to actually see in season if charge bolts can compete with other forms of damage.
Also the teleport nerf obviously hurts our mobility significantly so we'll have to work around that by gaining more movement speed for when we're out of teleport charges as we will most likely run out of them quickly once we get high cast speed. Overall however, StormCloud and Stormbolt seem untouched, meaning our mid and early power is still the same, an absolute monster. Our late game power is yet to be seen but should be still viable enough.